1. Field of the Invention
The present invention pertains to the art of clothes washing machines and, more particularly, to a noise reduction system for a washing machine.
2. Discussion of the Prior Art
In a clothes washing machine, it is not uncommon for a fair amount of noise to be developed during normal operation. For example, when a washing machine tub is rotated at a relatively high speed during an extraction phase of an overall washing cycle, an unbalance condition can cause considerable vibration and noise. Excessive vibrations can be detrimental to the continued reliability of the machine. In an attempt to avoid this problem, it is known in the art to provide a vibration detection system for sensing an actual or incipient unbalance condition and for altering the operation of the machine when a predetermined threshold is reached. Typically, known systems function to either reduce the rotational speed of the clothes tub or entirely shut down the machine to counteract an unbalance condition. In the art, various different vibration detection systems have been employed. For instance, it has been known to employ switches, particularly micro-switches, which are closed when excessive vibrations are encountered. Activation of the switches is relayed to a controller for altering the operational state of the machine. Other known systems provide rather complicated electronic sensing systems to perform a corresponding function.
Another major source of noise is caused by a pump typically used to drain water from the washing machine tub. The noise caused by the pump is particularly loud when the pump is starving for water during a spin out or extraction mode. Essentially the water is forced back and forth in a drain hose during pump starvation, thereby creating objectionable noises. While attempts have been made to address the problem of pump starvation in the area of dishwashers, significantly less effort has been applied in the area of clothes washing machines. In any event, there exists a need in dealing with noise produced by an unbalanced condition, pump starvation, or generally optimizing the noise level in a clothes washing machine.
Finally, it should be noted that prior art washing machines have typically been controlled by using either buttons or knobs to set desired washing cycle parameters, such as the desired fill level, load size, wash and rinse temperatures, along with washing operations, such as gentle, normal or light cycles typically based on the particular fabrics being washed. Using such buttons and knobs can be cumbersome, especially when one""s hands are full of clothing that need to be washed. Therefore, there exists a need in the art for a noise control system for washing machines which can sense and reduce noise caused by vibration or unbalance, noise caused by pump starvation and additionally, provide for an easy way to control the various washing operations of the washing machine.
A noise reduction system for a washing machine constructed in accordance with the present invention is used to control noises caused from various sources, such as excessive vibration and pump starvation, in a reliable, accurate and cost effective manner. More specifically, the present invention is directed to a noise reduction system for a washing machine, particularly a horizontal axis washing machine, which can sense excessive vibration and pump starvation through the use of a microphone. In accordance with the invention, the noise reduction system can sense actual or incipient unbalance conditions with the microphone. Once an unbalance or excessive vibration condition is sensed, a controller may alter the operation of the machine to counteract system imbalances. For instance, the system can either be stopped for a short amount of time to rebalance the clothing within the washing machine tub or alternatively, stopped altogether.
In a similar manner, the noise generated in an early stage of pump starvation can be audibly sensed. Based on the microphone inputs, the washing machine controller can evaluate the starvation condition and turn the drain pump off. Additionally, the microphone can be used to audibly sense when the water level in the tub is high enough to hit the washing machine tub or spinner, at which point the controller turns the drain pump on again.
An additional use of the microphone in a preferred embodiment of the invention is to optimize the noise level of the washing machine during spinning. The speed of the washing machine can be varied and noises generated at each speed are recorded to create a noise curve. Once a valley or minimum point is found in the noise curve, such speeds, which correspond to operational states of low noise, can then be used for future operations. Additionally, vibration itself can be correspondingly limited at the same time.
According to yet a further aspect of the invention, the microphone is connected to the controller of the washing machine in such a way as to allow the machine to respond to voice commands. Essentially, all commands that were previously given by input from either typical knobs, buttons or LCD panels may now be entered into the machine using simple voice commands, thus providing an efficient way to control the overall washing machine.
Based on the above, it should be readily apparent that the invention provides for a relatively simple, inexpensive noise reduction system which addresses the problems caused by vibration, pump starvation and other general noises found in a washing machine and, additionally, provides an efficient way of controlling the machine to optimize operational speeds and to simplify programming. In any event, additional objects, features and advantages of the invention will become more readily apparent from the following detailed description of a preferred embodiment of the invention, when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views.